FIG. 22 shows an example of a conventional stereoscopic-image pickup apparatus. FIG. 22 shows the pickup state of a stereoscopic image called horizontal-run body. FIG. 22A and FIG. 22B show the relationship between a camera and a pickup target before movement and the relationship after movement, respectively.
First, an object A and an object B are picked up with a camera 1 before movement (FIG. 22A). The object B is located more distant than the object A. A common axis (shown by one-dot chain line) passing through the objects A, B is perpendicular to a pickup face of a CCD 2 or pickup device. An optical axis (line passing through a lens 3; shown by two-dot chain line) of the camera 1 is away by a distance l1 to the left from the common axis (shown by one-dot chain line). In this state, the object A and the object B form images at a1 and b1 on the pickup face of the CCD 2, respectively.
Then, the camera 1 is moved parallel as shown in FIG. 22B so that the optical axis of the camera 1 is away by the distance l1 to the right from the common axis passing through the objects A, B. In this state, the object A and the object B form images at a2 and b2 on the pickup face of the CCD 2, respectively.
When displaying the images picked up before and after movement of the camera 1 as described above, for example, on a display unit using shutter glasses which control light transmission and interception, the displayed images will be as shown in FIG. 23. In FIG. 23, 11, 12, and 13 designate the image picked up before movement of the camera 1, the image picked up after movement of the camera 1, and the state that these images are displayed alternately (displayed images), respectively.
A shutter 14a is controlled such that a viewer sees the image before movement with his/her left eye L and the image after movement with his/her right eye R. Thus, the object A and the object B are seen as stereoscopic images protruding forward of a screen due to respective parallax.
FIG. 24 shows an example of an apparatus for seeing the stereoscopic images, wherein 20, 21, 22, and 23 designate a video camera, a reproducing unit, a controller, and a display unit, respectively. The above-mentioned images 11 before movement and images 12 after movement are displayed on the display unit 23 to correspond to the even field and the odd field, respectively. The viewer sees the displayed images wearing the shutter glasses 14. The shutter 14a is controlled by the controller 22 such that light transmission is done for the left eye L and light interception is done for the right eye R at the time of the even field, whereas light interception is done for the left eye L and light transmission is done for the right eye R at the time of the odd field, thus allowing the viewer to see a stereoscopic figure shown in FIG. 24.
In the above-mentioned image pickup of the horizontal-run body, however, it was necessary to accurately parallel-move the camera 1 in the cross direction, leading to difficult pickup. As will be understood from FIG. 23, the objects A, B are seen as protruding from a display surface (point at infinity on the display surface), which is visually unnatural, resulting in fatigue.